Tile Efficiency 101 (Part 2)

The last post on tile efficiency was kind of basic, so today’s article now introduces the concepts we are going to use in the future articles. Especially, Shan-Ten (how many away), Uke-Ire (the amount of tiles that move you one shanten closer to tenpai) and Good Shape Evolution (when your hand will evolve towards good shape). So, enjoy.

Source: http://beginners.biz/h_02.html

Useful Tiles and Tile Numbers

Mahjong is a game where you systematically discard once and again an unwanted tile from your hand.
Last time, I said that selecting your discard prioritizing the easy win is basic.

So, what should we select to discard concretely…

１．Number of tiles and probability

Ex1:

In ex1, as long as isn’t very dangerous, we should discard .

Let’s try to think it over. Why is it a mistake to discard or ?

Of course, it’s because discarding leaves us with a better wait.
Let’s try to compare them virtually.

Wait:

Wait:

If you consider the number of winning tiles, the former has 7 tiles, while the latter has 3.
Of course, since some of them might be in the hands of our opponents or in the dead wall, in reality,
you should naturally wait on 7 tiles, since it’s not like if you wait on 3 tiles they’ll be alive.

There are cases where there aren’t any remaining as well.
However, there is practically no way for us to tell how many tiles are remaning on the live wall.
That is because we are not psychic.

In reality, when comparing whether to wait on 7 or 3 tiles, judging that the wait is more effective is good.

“The more tiles you wait on, the better your wait is” is a basic concept in mahjong.
Ignoring this basic concept, it is not possible to win at mahjong.

The wait has more tiles.

＝ It’s more likely we’ll win on .

＝ It’s more advantageous to wait on .

It is important to play mahjong with this mindset.
Mahjong is not a game where you compete to see who has a better sixth sense, it’s a game where you compete to better evaluate advantages and disadvantages.

２．Number of uke-ire

In example one, we evaluated a tenpai hand, but if we also evaluate a hand that is not tenpai and compare whether there are too many or too few tiles, what to discard should become an obvious choice.

(…) — 3 shanten — 2 shanten ——- 1 shanten ———— tenpai ——————— Win

Let’s look at this graphic once again.

Since there is a large gap of distance until the win, it is hard to find the fastest way.
First, let’s find the fastest route to the next step (2shanten, 1shanten, etc), and think about the fastest route possible towards tenpai.

Using the number of tiles, the easiest wait to measure how close to the win the hand is, is to count and compare how many tiles will decrease the number of shanten.

Ex2

Ex2 is a hand 2shanten. Let’s count how many tiles transform it into 1shanten.

that’s 7 types and 23 tiles

<<(remember to substract the tiles already in your hand [1m, 4p, 2s] or visible on the board).>>

This is the number of uke-ire towards 1shanten. This is, the uke-ire.

Ex3

Ex3 is very similar to Ex2, but since it is also 2shanten or 2-away from chiitoitsu/Seven Pairs, the uke-ire is:

that’s 13 types and 35 tiles.

Its ukeire is far wider than Ex2, so it is clear that its shape is better than Ex2.

In this way, counting the ukeire of the hand, it is possible to measure a hand’s merit with numbers.

We will be using the value of uke-ire in the following lessons.

３．Evolving into good shape

tsumo:

If we think about the earlier concepts, by cutting when we draw , the hand is still 2shanten, but since the uke-ire increases, we must think of as a useful tile as well.

Useful tiles either:

A ： Decrease the number of shanten (uke-ire)

B ： Increase the number of uke-ire (good shape evolution)

one or both things.

Ex4

(pon) tsumo:

Ex4 is a decission about which wait to take.

With the current shanpon wait and even if we discard for a kanchan, the uke-ire is the same number: 4 tiles. In that case, let’s think about evolution towards good shape.

drawing number of tiles UP.

drawing number of tiles UP.

Since it can also improve to a three-sided-wait, keeping the shanpon wait is correct.

In cases like these where the uke-ire is the same, we use the technique of comparing evolution towards good shape.

The important thing here is uke-ire number has more value thangood shape evolution number.

First of all comparing the number of uke-ire before anything else is basic tile efficiency.

A ： Decrease the number of shanten (uke-ire)

B ： Increase the number of uke-ire (good shape evolution)

Rarely, there are also people who give A and B the same value, and people who sum and compare A+B.

In mahjong there are 2 kind of playstyle :
Digital style : based on probability and statistic.
Occult style : based on momentum, flow, miracle, or sixth sense.
Most of mahjong manga/anime adopt occult style.
Some of them adopt digital style.
No matter what style they use, mahjong is just a mahjong.
However, digital style is known as the best way to win the mahjong.

Occult Style could only be called something of “intuition” which is gained after probably countless games to the point where you can instinctively “feel” what hands the other players are going for, what tiles they could be waiting on, along with which remaining tiles that could be in the wall. Even without the exact depth of “knowing” their hands, you have certainly tapped into a depth of “understanding,” greatly limiting those possibilities, and from that, you have a strong sense of what moves to make based on that information.

It’s not about always making magical rinshans or dubious hell waits that turn miraculous, but certain “reads” can certainly lead to making some of these odd events to happen. Perhaps you could tell what tiles can easily overflow from your opponents’ hands, making a hell-wait pursuit riichi, sensing that another player likely holds most of the other player’s winning tiles. Taking a more extreme example, perhaps you could tell you have a high chance at drawing a certain tile after combining the discard pile with seeing two players going for opposite suit chinitsu/honitsu while the third is trying for a lower sanshoku, so you find yourself declaring riichi right before you could draw the last tile.

They call certain events miracles when they seem to defy the feat of ordinary probability, however, if you have more information that gives you a firmer grasp of the situation, perhaps that one “miracle” that others see outside of their reach is more possible than you think. For better or worse, it’s not Saki where you could unconditionally pull the same rare yaku out of a hat anytime, anywhere.

Is a double pair wait considered good as the trap play? Because double pair wait can not be easily read and discarding suji can be dangerous. The odds to win is smaller, but it can make your enemy get mad and lose their mind in the next game.

Is a double pair wait considered good as the trap play? Because double pair wait can not be read easily and discarding suji can be dangerous. The odds to win is small, but it can make your enemy get mad and lose their mind in the next game (especially when one of the pair is dora).

A trick you can use, is count your pairs. 4 pairs is chii-toi 2shanten, as 5 pairs is 1shanten. Remember that if you’ll go menzen, two pairs is the strongest possition (this is because you get 4 extra tiles to help you). So, the best thing you can do, is calculate the uke-ire “raw.” This is, if you have a closed wait “4,” a shanpon “4” a penchan “4” a ryanmen “8” and a tanki “3.” And you just substract the number of those tiles that you see in your hand (and the board). Likewise, a three sided wait would be 12 tiles, substract the one you already have in your hand, and it’s 11 (I automatically count it as 11, but just in case you don’t want to fck up).

If you always count them as you play, you can begin to easily notice even without counting, just by the structure, in most hands. When I look at the hand, I can easily distinguish hands with an uke-ire of between 8 and 20 as those are the most common. Any more than that, and I have to count a little more, but I normally just take all hands above 20 as “good enough” and in those cases just choose according to yaku/dora/final wait/etc.

The author says any hand with an uke-ire towards tenpai of 16 tiles is good enough. And fair enough, if my uke-ire is 16, I draw my tenpai 90% of the time. An example of not understanding this concept and failing is as follows:

一ニ三五六七 ②③ ６７９９ 北
The uke ire is 16, pinfu is confirmed. Here, you would keep pei as a safe tile, since having a ⑥ floating around in your hand or anything like that doesn’t help your hand. Assume you draw ②

一ニ三五六七 ②②③ ６７９９

If you have dora (one or more), discarding pei to keep the 223 shape is correct, as it increases your uke-ire to 20 tiles, by adding the 4 extra tiles of the ②②９９ shanpon. Given that the risk of discarding ② later on is not that big either, I believe this is the best.

Another common mistake would be

一ニ三五六 ⑦⑧⑨ ８９９ 北北

Here, discarding 8, 9 or north is generally a rather bad mistake. The shape -looks- bad, maybe, but it has a decent uke-ire, same as two ryanmen, 16 tiles. (四七７９北)
More so, if you get to tenpai with 7, 9 or North, you have a ryanmen. With 7, you have pinfu.
If you get to tenpai with 四or七, the 9-North shanpon is very easy to win with. If you have dora, consider to keep pushing ahead with this shape, as you’re not likely to improve it and 16 tiles is a good enough uke-ire.

I think I just used up most of the material for one of the next posts. orz